00:01
Okay, so here we're making a 95 % confidence interval estimate of the mean, and we have a little random sample of 124, 62, 805, 115, 131, 84, 121, 92, and 74.
00:21
So this is 10 data points, right? and we don't know the serend deviation of the population, which means we are going to do a t -term, sorry, a t -interval.
00:37
The formula for a t -confidence interval for means is x -bar plus or minus t -star times s over the square root ven.
00:45
So we're going to need the sample mean and the sample seren deviation from our sample in order to compute this.
00:55
And then we also need the t star, which you look up on your table with the appropriate degrees of freedom.
01:02
For a one sample t test like this, the degrees of freedom is n minus 1.
01:05
So that's going to be 9 in this case.
01:07
And when we look up 9 degrees of freedom and 95 % confidence, we get t star, the critical value for t equals 2 .262.
01:24
Okay, so i put all these numbers into my calculator to find the mean and standard deviation.
01:31
I just ran one sample, or sorry, one variable statistics...